Copying or enlarging camera.



J. BECKER. COPYING 0R ENLARGlNG-CAMERA.

APPLICATION FILED FEB. 24| 1914.

. Patented, Apr. 4, 1916.

4 SHEETS-SHEET 1- Inventor" J. BECKER.

COPYING 0R ENLARGING CAMERA.

APPLICATION manna 1914.

Patented Apr. 1926;

4 suzirs-suzzr a.

If? veni jw J. BECKER.

COPYING 0R ENLARGING CAMERA.

APPLICATION FILED FEB. 24, 1914.

; Patent-ed Apr. 4, 1916.

.4 SHEETSSHEET 4. f= nv= N7: 24 cm. FF'= 53 cm. NN= +5 cm F- M GA I g6 MF' =-l9 cm. MN +5 cm. MN: IO cm MF': 34 cm x (6 cm.

0 IO 20 3o .40 50 SCALE 3 "I 1 u u n u u u u n umTEDSTATEs P T NT F Jo sarn BECKER, or WASHINGTON, ms'rmio'r' or oouUMBIa.

- To all whom concede:

Be it known that I, JOSEPH BECKER, a citizen of the United States, residing at Washington, in the District of Columbia, have invented a' new and useful Improvement in Copying or Enlarging Cameras, of which the followingiisa specification. v

The presentpatent application is identified for convenience of reference in my related applicationsz crqpatents as Case Ab, and it makes. specific referenc'eto a number I -of such related applications orpatents as follows: Case A, Serial No. 26,647, filed Au- 11, 1900; Case B, Serial No. 42,957,

filed January 12, 1901; Case I, Serial No.

, 211,452, filed June 7, 1904; Case K, now

Patent 1,103,342 Case L now Patent.

1,126,352; Case"O,-,now Patent 1,103,343; Case T, now Patent 1,142,295; Case U, Serialw'No; 659,021, filed November 7, 1911; Case Y, Serial No. 732,488, filed November British Patent 24,292 of 1911;

' British Patent 29,701 of 1912; and'British using different lenses, the presentinvention is still partly useful. in combination with' Patent 5,317 of 1914.

The present inve tion relates to all classes length 7, equal 24 centimeters, for which a constituent .part of such mechanism, with the object ofproviding the three independentadjustments thatI'have discovered to be necessary to permit of settingand -regu-- lating any such mechanism for use with any one of different lenses.

-, If a given type of focusing mechanism (such as the linkage focuser of my said- Cases K and O or of my said liritishPatent 24,292/11, the radial cam focuser of my said British Patent 29,701/12, Or of my said Case U and that of my said Case Y, or the eccentric focuser ofmy said Case T) is already provided. With the three independent adjustments; that l are needed to permit of such adjustable mechanism togincrease the range of its adjustab'ility'; but the invention is primarily intended for use with focusing mechanism whichfdoes not contain within itself any direct meanspf adjustment; as,- for instance, the cyl ndrical cam gear'shown Specification of Letters Patent.

-' corms on Eumneme CAMERA;

in British patent to Thompson, No. 5,583

ing or enlarging camera with focusing mechlens having a :Eocal length f of24'cm-and provided with three independently adjustable, but normally invariable, elements, to wit, m, m, and the height of point A", all

H v Patented-Apr.4, 1916.

' f Application filed Februaryge, 1914. Serial No.820,695.

of which; have been properlyregulated for the lens used which has alfocal length phi (q?) of 28 cm with its nodal points NyNf situated and spaced as indicatedi-n the figure; Flg. 2 is. a Similar vertical 'section,tshowing how the left end-frame is'properly located and fixed daft-its carriage by focusing on r ght infinity. Fig.3 is another similar, sectlon, showinghow the right handend frame is properly located and ,fixedon its carriage by focusing on leftin-finity.- Fig. 4, with a table of dimensions "annexed, is the camera of Fig. 1 as it might be used, without lever transmission, with Many lens 13. of focal the mechanism 'inclosed in casing-X was specially designed. Fig. '5 shows the lens14 used in Fig. l with a table of its various dimensions as they .are after the bushes been mounted'onthe lens frame L. V

The bed 10 of the camera is provided with two side brackets, such as 11, which are fixed to the bench by screws 12' and which extend upwardly to constitute the vertical side bars of the lens support or lens frame L. The lens 14, which is fully determined for all present purposes by plotting the positions cm.) and a relatively large internodal space NN' of six'centimeters (6 cm.), the latter benigselected relatively large for clearness.

The upper inside walls of the bench are grooved, as at 15, to form a horizontal slideslideway. 17 for the foot l 8 of the object frame 0; and a clamp sdrew l9 permitsof 'way'for two carriages 16, 16. Carriage 16; itself is provided with a shorthori'zontal ids 17, foot 18 and clamp screw 19 at the by screws 20 a bracket 21 which supports a bearing 23 for a smoothly fitted pin 30, the common axis of pin and bearing being indicated by a dot A. Pin 30is rigidly mounted in a block 31 that travels in a horizontal slot 32 formed in the casing X which is fastened to bed 10 by screws 33, 34, 35. This casing X has a second horizontal slot 32' for a block 31', froni'which projects a ,pin 30 whose axis is indicated by a dot A.

Blocks 31, 31' are connected by focusing mechanism of any type adapted for use with acamera having its lens frame stationary, and which is inclosed in casing X to oblige such two blocks 31, 31' to move simultaneously and in the same direction, with a varying velocity ratio such as required for a lens of a definite but unknown focal length f.

Let a dot D indicate the so far unknown position into which the left hand axis A would be brought if this inclosed focusing mechanism could act, or be set, to carry the right-hand block 31 with its axis A to right infinity; and let a dot D indicate the so far unknown position that the right hand axis A would assume if the same inclosed focusing mechanism could act, or be set, to carry the left hand block 31 with its axis A toleft infinity. These two dots D and D, when properly located, constitute the inner terminals of the two co-varying constant product space elements AD and D'A' of the focusing mechanism. That is to say, if U, V, W, Fig. 1, be three vertical marks on casing X indicating any three arbitrarily selected positions u, '0, w of the object terminal A; and if U, V, W be the three corresponding vertical position marks of the three pomclosed in casing X, then the horizontal distances ofdots D andD from these vertical marks will formponstant products as follows:

'uD.D'u=f 1)": 'vD.D"v'=f 2) -Df rer As long as the positions of D and D m unknown, the six factorsuD and D'u', ed and D o, 101) and D '10 must themselves remain unknown; but the, four intervals u'vf; m0, and uv', vw', or their equivalents UV, VW, and UV', VW are always directly measurable on casing-X. In the present instance If now the two unknown intervals VD,

D'V be designated by VD sycentimeters 0 DV'= equations 1, 2, and 3 may be re-written in the following-formz. v

'By substituting the above measured values sitions u, o, w of the image terminal A of a, b, and a, b in these equations 7 and 8 as determined and located by the mechanism we find: j

Dy=y (24 36)- X 33) (24x8) 16 cm.

Therefore, by measuring off 16 centimeters from V to the right, we locate D, and by measuringoif 36 centimeters from V to the left we locate D.

In view of equation 5, we might, if desired, futher derive cept as serving to establish the principle that any focusing mechanism is fully detergninable for all present purpose from three 24 X 36 36 cm.

Carriage 16 has fixed to its under side by screws 20 a bracket 50 which is provided with a straight slot 51. This slot 51 is preferably made inclined somewhat toward the right as shown; but it might be vertical or inclined at any other angle. Ashouldered pin 52 that fits snugly in slot 51 may be slid along to any desired point of such slot and there be firmly clamped to the bracket 50 by nut 53 and Washer 44. This pin 52,

whose'axis is indicated, in Fig. 1 only, by

' a'dot Af,and pin 30., whose axisis A, are

both engaged in the radial slot 5 1 of a slotted lever 55 which is pivoted by a pin 56 to a block 57. The block 57 is clamped to the camera bed 10 by screws 58, 59, which i also serve as guides for the walls of the horizontal slot 62 formed in block 57 to pro vide horizontally guided adjustment for pin 56, and forits axis indicated by point C.

The two slots 51, 5 1 are of the same width as seen in Figs. 1, 2, 3 to provide a smooth but close fit for the pins 52 and 30, which are made exactly of the same diameter.

The two end frames 0 and I are preferably made open with removabie screens 66 and 66 so that either, frame may be focused on infinity, through the other, without removing the other frame by simply removing the screen 66"or 66 contained in such other frame. i

The central. point of the object plane 66'isat P, and the central point of the image plane 66 is at P and any focusing mechanism that is operative must keep these two points respectively coincident with two conugate foci of'the lens in conformity with N ewtons formula, to wit:

where phi 12) is the generally unknown focal length FN or NF of the lens tobe used. This result is insured by means of three independentadja....tments, to wit: 1,

' adjustment of the object frame connection on'carriage 16 at the left; 2, adjustmehtof the image frame connection on carriage 16 ,at the right; 3, adjustment of the constant velocity ratio CA/CA' in lever 55.

f its carriage 16 by, tightening screw 19;

' 'nection.P' I object carri g' 16 which is t 1. Adjustment of the object frame can ,80 is withdrawn to free the hen slid up into its zero p s1 ion, the position of Fig. 2, where axis A has been brought into coincidence with axis D and distance AD is m'Z, To insure this coincidence and to temporarily lock carriage 16 exactly in this its zero position, pin 30 is reinserted in hearing 23 so as to project as a slide bolt from bearing 23 into, bore 40. While carriage '16 is thus held in its zero position, the image screen 66. is removed, the clamp screw 19 is loosened and-the object frame 0, now free, is sharply focused on infinity or parallel rays from the. right, and then it is locked to Point P is now coincident with F, as seen in Fig. 2, and A is coincident with D; that is to say, distances PF and AD are both m'Z.

Pintle 30 is now withdrawn from bore 70 sented by the length of a similar imaginary connecting'bar 00, Fig. 1; and the adjustment, thereforeyhas simply served to make these two imaginary connecting bars at and w exactly equal to each other. The adjustment also results in making the'incli'ned line.

that would join points P and A of the object frame in Fig. 2 coincident and identical with the inclined line that would join the fixed points F and D of the lens frame; so that, after adjustment asin Fig. 1, where. the

two lines PA and FD are separated, they remain equal and parallel, determining a parallelogram PFAD. with its horizontal sides PF and AD variable, but constantly equal to each other PF being the left va'riable Newtonian space element of'the lens,

and AD being the left variable Newtonian space element of the mechanism.

Adjustment of the image frame 00anectz'0n.Pin 52is shifted to any high position in slot 51, such as that seen in Fig. 2, and it is temporarily clampedto bracket 50 in such position by lightly tightening nut 53. Pin 30 is now removed from block 31 to free vrriag'e 16', which is then shoved along on 10, causing lever 55 to'. turn on C as fulcrum. This motion of carriage, I 16 is continued until the slot 54 of lever 55' has been brought into exact register with' bore 40 at D, as indicated in Fig. 21; and such registration is insured and maintained by inserting pin 30' through slot 54,"as lock bolt, into bore 40. The lower end C of lever 55 should now be 'fi'eed'by loosening screws 58, 59; and pin-30, Fig. 2, is thus prepared to act as a stationary fulcrum for lever 55, while carriage 16 is slid to the left, causing block 57 and point C to shiftto, the right. This shifting is continued Thereupon block '57 is firmly. clamped to bed 10 bytightening screws 58 and 59. Carriage. 16' and lever '55 are now held in what constitutes their zero position not only for the'present lens 14:. but for all sizes and until the bracket slot 51, and the lever slot 54, have been brought into perfect register as in Fig. 3, and the registration of thetwo slots is insured by inserting a locking block forms and types of lenses. The fulcrum block 57 may, therefore, be more firmly fixed to bed 10 in its thus determined permanent location by inserting a screw or other permanent fastener 61 that fits nicely throu h a hole 60 of block 57 and is driven into t e wooden base. While carriage 16' is thus held in its zero position, Fig. 3, the object I screen 66 is removed, the image screen 66' is inserted, and, -having loosened clamp screw 19, the image frame I is; set shai-ply in focus on parallel rays from the left, .and then the screw 19 is retightened to lock 'the image frame I inits thus automatically determined' proper relation to its carriage 16.

The equality of the stillundetermined imaginary bars m'sand m' is thus established for. any height thatmay later be found for the path D"A- by means of the third adjustment. V

In order to set the carriage 16 free for such third adjustment, pin is now withdrawn from bore 40", and block 63 is withdrawn from slots 51, 52.

3. Adjustment of the constant velocity ratio 0A"/0A.The only thing that remains tobe done is'to determine the proper value of the eloc'ity-ratio CA"/CA'. This ratio CA"/CA-' is varied at will by chang' ing the level of the horizontal path described by pin 52; that is to say, by shifting the said pin 52 from the high position of Fig. 3, order to make adjustment 2, down to-the proper elevation which it must occupy in order to secure the displacements that are required by the particular lens 14 which is being used. I

Immediately after completion of adjustments 1 and 2, pin 30 and block 63, seen in Fig. 3, were removed, so that pin 52 now constitutes the only remaimng connection between the carriage 16 and lever 55, and

the image frame I can be slid along freely on bed 10. The object frame 0, however,

having been coniie'cted with-block 31 as the result of adjustment 1 is not'free, but it may be brought into any desired position on bed. 10, that of Fig. 1, for instance, by actuating" the focusing mechanism ii'iclosed incasing X; and this operation simultaneously brings the terminalsjjA and A into the positions V and V shown in Fig. 1. The object frame 0 is then temporarily clamped to bed 10 in such selected position of Fig. 1 and a test object is mounted in its temporaaily held object plane B. The image plane P is now sharply focused. on the object plane P by sliding the carriage 16' along on bed 10, and when the sharpest focus has been found the imageiframe I'is temporarily clamped to bed: 10 in its thus' determined conjugate position. Pin 52 is now loosened and slid down in slot 51, until the lever 55, turning on C has been brought into the position of which was arbitrarily selected in Pi'n A Fig. 1, will now travel along the horizontal line A D" and at suchrate as to pass successively through the three points u, 'v-, w" as pin A passes successively through the three points to, o, w. The zero position of A is D just as the zero position of -A' is D and the ratio DA"/D'A' of corresponding displace ments is equal to the constant ratio CA/CA of the two variable lever arms CA" and GA. This ratio is most conveniently measured on the vertical through C, Fig. 1, where the two lever arms CA and CA are shortest, being found equal -.to 98 and 72 centimeters, respectively; and we,-

therefore, have: D"A" CA 98 49 It was established above, by means of' equations 1 to 9, that the' original focusingmechanism contained in casing X- determines constant product space elements AD and D'A' in accordance with the formula nnn'ae z xar 1 Dividing equation 13, term for term, by

equation 12 and noting that the space element AD is identical in the two equations, we finally obtain 'D"A 2 28x28 49 fwhich isin exact accordance with equation 11, as it should be, that isto say, omitting numerical values, we have the general algebraic equation 'of the object frame space element AD are u-D l-S cm TDIIG cm 10D: 8 cm The three corresponding and mechaniare:

i ka igia 'ss ficm 'atem and the three derivedjim ge-frame space ele- D"c" #49 cm I "D"w=98 cm I .The longitudinally adjustable connections m :al9 cm m="w= cm {The horizontal distance'DcZ between the orlginal zero points D, D- is I v v Dal 2 6cm and the horizontaldistance Dd between the T final zero points D, D is I Dd l8'cm and, in' accOi'dance with equation 5 of my sald British- Patent 29701/12, we must, and

' do, have To perm it of using the focusing mechain'closed in casing X and originally made for afllens of focal length f equal 24 "cm, in combination-witha lens of focal length (to) equal to or smaller than 24 emf.- the pin. 52 must have free adjustment 1; ,thr'oughi-f the :position where the. distance .CA" is-fe ca-ctlyequal to CA! without being \,interferedjwithfby pin 301* For this reason ithe lever''-' 5F5.- is P de extra thick and the" p ns and 52' ale made so as to project into s'lot 5 4 from opposite sides, less than half way-through the thickness of the lever.

Slot 51in .bracket can be made suiticientlydong' to-extend below the horizontal path ofaxis C so that axis 0 may be brought. into its proper permanent position by simply-bringing it into register with the middle of such extended slot, and this either with or without the aid of the auxiliary lock block ea as may be preferred.

General remarks.

TThe original focusing mechaand the two inner terminals D, D absent,

was of thetype represented by case 7 page 12, of my said British Patent 29701/12.

Nora 2.'By' structurally adding the two inner terminals D D' it becaliie' of the type represented by thecomplete form shown in Fig. 15 of the saline patent.

Ne ir-In, the final focusing gear comforthe actinic region ofthe spectrum, or

Newtonian space element's AD and DA, Fig. 1, the inner terminal D is purely imaginary and the mechanism is of the type represented by'case 3', page 12, of the same said British Patent 29701/12.

NOTE 4:.Any focusingmechanism represented by one of the twelve cases'noted on page 12 of my said British Patent29701/12 can first be converted into my complete form, Fig. 15 of the same patent, by structurally adding the omitted Newtonianterminal or terminals as was done above for the focusing mechanism in casing X, and then the principles herein disclosed can be applied without difficulty.

NOTE 5.The general three-point adjustment for three diflerent finite values of the copying factor n as illustrated in Fig. 16 of my said British Patent 29701/12 is applicable in the present case, being particularly valuable here, as in both of my said prior British Patents 24:292/11 and 529701/12 wherever the lens used is specially designed else specially designed for values of the copying factor n ranging between given finite limits.

NOTE 6.-The present invention may be considered as a development of the principles' first enunciated in Notes5 and'6, page 20, of my prior U. S. application, Case Y, Serial No. 732,488, filed November 20, 1912.

NOTE 7. The principles involved are most easily explained when the lens is stationary, as in the form selected for illustration; but either end frame ,0 or I- might be the stationary frame instead, and in certain forms it might be advantageous to have all threeframes 0, L, I freely movable on the slideway 10, with casing X direetly-'connected to and moving with the lens frame;

Nor-n 8.Inevitab1eerrors in grinding and mounting, and, principally, unavoidable variations in the refractive index of diiferent casts of the same optical glass, make it extremely difficult to produce two objectives exactly alike in all particulars; and therefore, all lenses must, for present purposes, be treated as different lenses. Hence,

even in constructing a camera for use with a given type and size of lens, as in Fig. 4, it 1s preferable to use an ad ustable form of my invention, because the ad ustments permit of making proper allowance for all accidental 0- carriages, as in Fig. 4, to move the points P and P through the conjugate position determined, for any lens of 'focal'length 7' equal to 24 centimeters, by either one and hence both of the lens "formulae given as equations land 2 of my said Case L or of my said British Patent 5317/14. I

N or]: 10.Theprinciple that focusing gear having a constant velocity ratio'transmission, with adjustments for changing the velocity ratio as required to adapt'the gear for use in combination with any one of different flenses', must change such velocity l "int'io in proportion to the square of the focal length of the lens, was established as a general principle for optical focusers in a paper dated January 23, 1905, of my'said Case B, and this focus-squared principle is involved in my so far described focusers, as follows: first, with continuously adjustable velocity ratio in the approXi-matel accurate optical focusers, Figs. 33 and 5 P of m gfsaid Case A; secondly, with 3 value ad- 311 able velocity ratio inthe approximately accurate optical focuser, Fig. 10 of my said Case B, where the 3 values of ,the focal length areas 3, 4, and 5, while the corresponding 3 values of the velocity ratio are as 9, 16, and 25; thirdly, withfixed velocity ratio in .the theoretically accurate optical focuser, Fig. 2, of my said Case I; fem-tidy,

with continuously adjustable velocity ratio in the theoretically exact mechanical focuser of the present application, Case Ah. As this fourth and herein made disclosure shows my first complete and theoretically exact solution of the mechanical problem involved in the said focus-squared principle I am making all claiins thereon in the present application, Case Ab.

No'rn 11.'Figs. 33 "and'j5i" of my said Case A and Fig.- 1O of my'said Case B disclose .optical focusers having an approximately cons'tantvelocity rati'o transmission such velocity ratio; as required by any one of different camera lenses and in such manner as tobe substantially independent of another adjustment so as to permit of easily securing exact two-point correspondence between the focuser and the camera lens;

but the present application, Case Ab, con-- with adjustments for: changing the value of.

Norn 12.-I am aware that Cook, in Fig. 3 of his British Patent No. 12,734 of 19 04 shows a slotted lever g which might eas ly be confounded with my constant velocity ratiolever but such Cook lever 9 moves its pintles b and 7' along paths that are perpendicular instead of parallel, and t really constitutes the varying velocity ratio focusing mechanism proper.

NOTE 13.-In accordance with a convention adopted in Figs. 12 to 15 of my said Case T, the imaginary bars w and x of Fig. 4, being both invariable, after the lens 13 has been mounted, are shown black; whereas the imaginary bars m and m, being adjustable, are left white; and in Fig. 1, according to the same convention, the imaginary bar w, being alone invariable,- is alone shown black.

No'rn 14.The horizontal adjustment of fulcrum C, once made for a given lens, is final for all lenses. It is, therefore, an auxiliary adjustment which should not be confounded with any one ofthe 3 main adjustments that are at alltinies necessary, as at 19, 19, and 52, to secure 3-point correspondence of the focuser with any one of different lenses; whereas such .auxiliary adjustment serves merely to insure that the last two of the said 3 main adjustments shall be absolutely independent; and I have found that a similar auxiliary adjustment is useful in focusers having only 2 main adjustments, as in the approximately accurate optical focusers, shown in Fig. 33 of my said Case A and Fig. 10 of my said case B.

No'rn 15.The velocity ratio phi square on f square (o /f of terminals A and A, being constant by equation 14, is evidently equal to the ratio of any .simultaneous finite-displacements of such terminals, and any mechanism that is capable of producing simultaneous displacements of A andv I, A in such constant ratio must be consid- 110 cred as an equivalent of my lever transmission CAA. See Robert lVillis, Princ-iples of Mechanism, London, 1870, pages 12 and13, article 20. The velocityratio of terminals A and A, on the other hand, 11 is necessarily a varying velocity ratio 1 whose value changes'with every change in position and can only be determined as the ratio of infinitely small simultaneous 'displacementsi NOTE 16.-Any focusing agent may according t0,the' rules of the English language be termed a focuser. In my speci=--- fications, however, the term focuser has a restricted meaning which is most easily specified by the citation of existing patents. Thus optical focusers, in the sense in which I use the term, are seen for instance in the focusing means of ,the following patents, to wit: Niconr, 71,205 of 1867; 130

1890; Gogswell, 484,179 of 1892, and Ger man Patent 188,342 of 1907' to du Bois.

Reymond; whereas fmccha'zgql focusers, 1n the sense in wh ch I use the tfinfare .seen for instance in the focusing means of.

the following patents, to wit: German Patent 102,004; of 1897 to Carpentier, my

said Case K, now Patent 1,103,342, and my said Case T' now Patent 1,142,295

I claim 1. In a copying or enlarging camera comprising a support for the object plane,

a support for the lens and a support for the image receiving plane, and ways for guiding two of such supports with rela-. tion to the third in order to van}? their relative distances as required to produce images of various desired sizes, of focusing mechanism for mechanically connecting such three supports/to keep the said end of image planes mutually in focus oneach other throughout all displacements of the supports, such mechanism comprising a constant velocity ratio mechanism with adjustments to vary the velocity ratio as required for different lenses.

2. In a copying or enlarging camera com'- prising a support for the object plane. a support for the lens and a support for the imagelreceiving plane, and ways for guidingtwo of such supports with relation to the third in order'to vary their relative distances as required, to produce" lmages of varlousv desired sizes, of focusing mechanism for mechanically connecting such three supports tokeep the said end or image planes mutually in focus on each other throughout all displacements of the supports, such mechanism comprising a constant velocity ratio mechanism with adwstrnents to vary the velocity ratio as required for different lenses;'also adjustments in two of the three normally rigid connections that must be established between such mechanism and the said three supports respectively.

3. In "a copying or enlarging camera comprising a support for the object plane, a support for the lens and a support for the image receiving plane, and ways for guiding two of such supports with'relation to the third in order to vary their relative distances as required to produce images of various desired sizes, of focusing mechanism for mechanically connecting such three sup-' ports to keep the said end or image planes mutually in focus on each other throughout all displacementsof the supports, such mechanism comprising a constant velocity ratio mechanism with adjustments to vary the velocity ratio as required for different lenses; also adjustments in two of the three normally rigid connections that must be established between such mechanism and the said three supports respectively; and means forthe purpose set forth:

to permit of reducing the Newtonian space elements of SUClIJDQChaHISHi to zero. .value,

4. The combination wit afor determining the said in-focus relative position of the said supportsecprresponding to any given distance ofthetsaid object; such focuser comprising relatively'movable elements whose relative position is determinable as dependent upon the distance of the said object from the said lens support, also mechanism connecting the said relatively movable focuser elements with the said lens support and the said image plane support; such mechanism itself comprising a constant velocity ratio transmission; such transmission having adjustments for changing the value of its said constant velocity ratio in proportion to the squareof the focal length of the particular lens that is to be used in the combination.

The combination with a photographic camera comprising a. support for a lens,-

a support for an image plane, and guides to permit of changing the relative position of said two supports as required to set the camera in focus on an object; of a focuser for determining the said in-focus relativeposition of the said supports corresponding to any given distance of the said object; such focuser comprising relatively movable elements whoserelative position is determinable. as dependent upon the distance of the said objectfrom the said lens support, also mechanism connecting the said relatively movable focuser elements with the said lens support and the said image plane support; such mechanism itself comprising a constant velocity ratio transmission; such transmission having adjustments for changing the value of its said constant ,velocity ratio in proportion to thesquare of the focal length of the particular lens that is to be used in the combination; such constant velocity ratio transmission comprising a lever and another, part with a pivot pivotally connecting such lever and other part, such pivot being adjustable along said lever and on the said other part 1n such manner that the two paths of adjustment shall be parallel when the said camera in focus on an object; of a focnscr photographic camera comprising a support for a lens, a

for determining the said in-focus relative position of the saidsupports correspondmg to any given distance of the saidobject; such focuser comprising relatively movable elements Whose relative position'is determinable as dependent upon the distance of the said object from the said lens support, also mechanism connectingthe said relatively movable focuser elements with the said lens support and the said image plane support; such mechanism itself comprising a constant ve1oc1ty rat1o tIaIlSIIllS;

, sion; such transmission havlng adjustments for changing the value of its said constant velocity ratio in proportion to the square of the focal length of the particular lens that is to be used in the combination; such consuch manner that, the two paths of adj-ust'-' stant velocity ra'tio transmission comprising .a lever and a pivot pivotally connecting said lever with the said image plane support; such pivot being adjustable along said .lever and on the said image plane support in ment shall beparallel when the sa id -l ever and image plane support occupy the relative position that they shouldoceupy 'avhen" the said object plane i s at infinity. V

7. The combination with a photographic camera-' comprisingjasupport for a lens, a support for an image plane, and guides to permit of changing the relative position of said two supports as required to set the camera in focus on an object; of a focuser for determining the said in-focus relati 'e position of the said supports correspond-' tively movable focuser elements with the said lens support and the said image plane support; such combination having main adjustments to permit of securing exact correspondence of the said focuser with any one of difi'erent lenses for at least 2 .differently distant positions of the said object; and an auxiliary adjustment, such as 'that of fulcrum C, to permit of making two of such main adjustments absolutely independent. I

8. The combination with a photographic camera comprising a support for a lens, a support for an image plane, and guides to permitof changing the relative position of said two supports as requlredto' set the camera in focus on an object; oflafocuser for determining the said fin-focus relative position of the said supports corresponding to any given'position of the said ob ject; such focuser. comprising relatively movable elementswhose relatlve position,

is determinable as dependent upon the position of the said object, also mechanism connecting the said-relatively movable focuser elements'withethe said, lens support 'and the said imagei plane support; such inechanism itself co iiprising a substantiallg constant velocity fra'tio transmission; suc

transmission having-adjustments for changing the value of its constant velocity ratio substantially in proportion to the square of the focal length of the particular lens that .75

is to be used in the combination. v

Intestimonywhereof, I have signed my name to this specification in the presence of two subscribing witnesses. i

' JOSEPH BECKER. lVitnesses:

MARY E. CowELL, H. P. HOWARD, Jr.

copies of patent may be obtained for five cents each, by addressing the Commissioner of Patentl.

Washington, D. C. i 

